Electric fuel igniting



' 1,694,053 w. K. BOOTH ELECTRIC FUEL IGNI-TING Original Filed Sept. 18.1922 OVMdK M IN V EN TOR.

ATTORNEY Patented Dec. 4, 1928-.

' UNITED STATES PATENT OFFICE.

WILLIAM x. 300cm, or cnrcaeo, ILLINOIS, assrouon 'ro ELnc'r'RoILsnmxca'rn,

AN ASSOCIATION comrosnn or c. r. JAEGER, L: M. RUTLEDGE, WILLIAM-L.MORRIS,

AND WILLIAM K. BOOTH.

ELECTRIC FUEL IGNITING.

Application filed September 18; 1922, Serial No 589,029. Renewed April30, 1928.

trolled fuel feeding system for furnaces for burning oil, gas, finelydivided fuel, and the like. Among the objects of the invention are: torovide means for stopping the delivery of fuel when the igniter isbroken; to delay the flow of fuel until the igniter is in operation; toput the igniter out of service after combustion takes place; and toautomatically maintain the fuel feeding .device in operation. Otherobjects will appear hereinafter.

In the accompanying drawinglthe .figure illustrates an electric ignitingsystem embodying this invention.

In an igniting system of this kind it is desirable not only to delay theadmission offuel until the igniter is in condition for igniting, .butalso to cut out the igniter when it has performed its function. Avariable resistance may be used to accomplish the latter result and aretarding device in connection with the igniter will'perform the firstmentioned function.

Referring'now more. particularly to the drawing, a furnace 1 is fed withfuel from a nozzle 2in connection with a fan or blower 3 which receivesfuel through an inlet 4. An

I electric motor 5 is connected 'to the fuel delivery device 3 andreceives current from sup ply mains 10 and 11 as hereafter described.

- Within. the furnace is an igniting. coil 6 suit ably supported out ofthe path -7 of the flowing fuel from the nozzle 2, and within the pathof the burning fuel, and suitably located within the furnace 1 to beacted upon by the heat thereofis a variable resistance 8 preferablyencased in a refractory material-9.

The igniting'coil has conductors 12 and 13' connected at the endsthereof and extending without the furnace. and the variable resistance 8has relatively movable contacts-Maud 15 which are adapted to makeconnection when the resistance, 8 becomes sufiiciently resistance 8 usedfor cutting out the current through the igniter coil 6. A retardingswitch R has a magnet winding 22 inserted with igniting coil 6 with adash potdevice 23 for preventing the rapid closing of this switch." Ifdesired, the main and cut out switches and the current through thevariable resistance 8 may be changed from the main circuit by means of atransformer T.

In the thermostat is a variable arm 24 connected by means of a conductor25 to one side of the transformer T and adapted to make connection witha contact- 26 or a contact 27. These contacts are connected byconductors 28 and 29 respectively withwindings 19 and 20 and thence byconductors 30 and 31 with switch contacts 32 and 33. The main switch hasa pivoted arm 34 engaging either one of a the contacts. 32 or 33 and isconnected by a conductor 35 with, the opposite terminal of thetransformer T. If the arm 34 of the main switch is in connection withone of the conspondingly. with respect to the switch contacts 38. Whenthe thermostatic arm 24 engages the contact 26 a circuit as traced aboveis closed through the winding 20 closing the...

switch bar 37 and when the winding 19 is energized the arm 34 is swungto separate the contact bar 37 from its contacts 38. soon as this mainswitch S is closed by the actionof the thermostat, a. circuit iscompleted from the main 11, contacts 38, and contact bar 37,

conductor 39, the winding 22,conductor 12, igniting coil 6,'conduetor13, back contacts 40 and contact bar 41 of the cut out switch C andconductor 42 to the other main 10. This will energize and heat up thecoil 6 so that it will ignite fuel.

A circuit-is not immediately closed to the motor-5 because the maincontacts 43 of the cut out switch C are not connected b the contact bar41. As soon, however, as t e retarding switch R is permitted to beclosed by the retarding device 23, a circuit is made from bar 45 andconductors 46 and the motor 5' to the other main 10. As soon as themotor is in operation fuel is fed through the nozzle 2 which is ignitedby the igniter 6, and as the igniter is out of the path of the flow offuel it is not directly heated thereby.

The resistance 8 is in series with the windthe conductor 39 throughcontacts 44, contact from the secondary side of the transformer asfollows: from conductor 25, conductor 16, resistance 8, conductor 17,winding 21 and conductor 35, back to the transformer. The variation ofthe resistance is such as to cause the connection of contacts 14 andwhen the resistance 8 becomes heated, and the resistance 8 prevents theflow of enough cur-- rent through the winding 21 to raise the cut outswitch bars 41. As soon, however, as the contacts 14 and 15 areconnected by the movement of the resistance, the latter is cut out andan" increased current will flow through the winding 21 which will drawup the contact bar 41 making connection with the upper contacts 43 andbreaking connection with the lower contacts 40. This will break thecircuit including the igniter and the winding 22 of the retardlng switchIt. It closes a permanent connection for the motor from the conductor 39which is connected by the switch S to the main 11 through conductor 47,contacts 43, contact bar 41, conductors 48 and 46, motor 5, back to theother main 10. The system will continue to furnish fuel in this manneruntil the thermostatic arm 24 moves in the opposite direction to engagethe contact 27. This will close a circuit from the secondary side of thetransformer T by way of conductor 25, conductor arm 24, contact 27,conductor 28, winding 19, conductor 30, contact 32, arm 34 and conductor35, back to the other side of the transformer secondary. This will drawthe arm 34 from its engag ment with the contact 32 to engage the contact33, and it will drop the contact .bar 37 from its connection with thecontacts 38, breaking the circuit for the motor 5. This will stop thefeeding of fuel and place the whole system in the condition assumed forthe start.

The resistance 8 cools rapidly and separates the contacts 14 and 15 andthe motor cannot be started immediately, first because the con tact bar41 will drop to engage the lower contacts 40 as soon as the contacts 14and 15-are separated, and because the other switch 45 cannot be closedrapidly on account of the retardin device 23. It is apparent therefore,

that fueI cannot be delivered untilafter the igniter is in operation andafter the igniter has successfully performed its function it will be putout of service until it is again required. The system is entirelyautomatic, requiring no manual attention. If the igniter is broken, themotor cannot be started in the first place as the winding 22, in serieswith the igniting coil 6, cannot be energized. 'In starting the motor itis connected in parallel with the winding 22 and the coil 6 in series.but

after the operation of the cut out switch 0, the motor is connecteddirectly between the supply mains.

I claim:

'1. In an electrical fuel igniting system, a fuel feeding motor, anelectrical igniter, a switch relay in series with the igniter operativeto close a starting circuit to the motor, and electrical means for opencircuiting the igniter, and the relay and closing a new running circuitto the motor.

2. In an electrical fuel igniting system, a fuel feeding motor, anelectrical igniter, a retarding switch relay in series with the igniter,means to supply current to the igniter circuit and to the motor, aswitch operated by the relay to close a starting circuit to the motorafter the igniter receives current, and electrical means for thereafteropen circuiting the igniter circuit and closing a new running circuitfor the motor.

3. In an electrical fuel igniting system,

fuel feeding means including an electric motor, an electrical igniter,means for delaying the starting of the motor until after the igniter isin operation, and electricalmeans controlled by the heat of combustionfor open circuiting the igniter and for closing a new running circuitfor the motor.

4. In an electric fuel igniting system, the combination with fuelfeeding means including an electric motor, of means for closing astarting circuit to the motor, a fuel igniter, and anelectro-responsiv'e means controlled by the ignited fuel for openingthestarting circuit for the motorand for closing a running circuittherefor. I

5. In an electric fuel igniting system,the combination with fuel feedingmeans including an electric motor, of an igniter, a temperaturecontrolled electro-responsive main switch, means for closing a startingcircuit for the motor after the igniter is in service, andelectro-responsive means for-thereafter opening the starting circuit andclosing a running circuit for the motor.

6. In an electric fuel igniting system, fuel feeding means including anelectric motor, meansfor igniting the fuel, different starting andrunning circuits for the motor, a resistance controlled by heat forshort circuiting contacts for said resistance, and electro-responsivemeans in series with said resistance operative to connect either thestarting or the running circuit for the motor depending upon thecondition of the resistance.-

. WILLIAM K. BOOTH.

